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Structure–property relationships in photopolymerizable polymer networks: Effect of composition on the crosslinked structure and resulting thermomechanical properties of a (meth)acrylate‐based system
Author(s) -
Ortega Alicia M.,
Kasprzak Scott E.,
Yakacki Christopher M.,
Diani Julie,
Greenberg Alan R.,
Gall Ken
Publication year - 2008
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.28732
Subject(s) - materials science , polymer , glass transition , acrylate , elastomer , ultimate tensile strength , ethylene glycol , ethyl acrylate , composite material , polymer chemistry , interpenetrating polymer network , copolymer , chemical engineering , engineering
Photoinitiated polymer networks were formed by copolymerization of tert ‐butyl acrylate with di(ethylene glycol) dimethacrylate (DEGDMA) or poly(ethylene glycol) dimethacrylate (PEGDMA). The degree of crosslinking was systematically varied by modifying the weight fraction and molecular weight of the dimethacrylate crosslinking agent. An increase in effective crosslink density with increasing crosslinking agent concentrations was confirmed by decreasing equilibrium swelling ratios ( q ) and increasing rubbery moduli ( E R ). Glass transition temperatures ( T g ) varied from −22 to 124°C, increasing with increasing DEGDMA content and decreasing with increasing PEGDMA content. Tensile deformation behavior (at T g ) ranged from an elastomeric‐like large‐strain response for lightly crosslinked materials to a small‐strain brittle response for highly crosslinked networks. At low crosslinking levels, the strain‐to‐failure of the network polymers decreased quickly with increasing crosslinking agent concentration. The stress at failure demonstrated a more complex relationship with crosslinking agent concentration. The effect of composition on network structure and resulting properties ( q , E R , strain‐to‐failure) decreased as the crosslinking agent concentration increased. The results reveal trade‐offs in T g , E R , strain‐to‐failure, and failure stress with composition and network structure, and are discussed in light of the wide range of potential applications suggested in the literature for (meth)acrylate‐based photopolymerizable polymer networks including biomaterials and shape‐memory polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008